Mobile Tracking

ABSTRACT

A method of tracking a first wireless communications device using another computing device, such as a second wireless communications device, includes obtaining current position data for the first wireless communications device and obtaining one or more of speed data, time data, and path data for the first wireless communications device. The first wireless device then transmits the current position data and at least one of the speed data, time data and path data to the second wireless communications device or other computing device. In addition to current position data, the speed, path and time data facilitate tracking of the first wireless communications device. When a first mobile user wants a second mobile user to follow him, the first mobile user can put his device in “follow me” (tracking) mode. This is particularly useful when the first and second mobile users are traveling in respective cars or other vehicles.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/950,285filed Dec. 4, 2007, the entire disclosure of which is herebyincorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to wireless communicationsdevices and, in particular, to wireless communications devices havingGlobal Positioning System (GPS) receivers or other suchpositioning-determining capabilities.

BACKGROUND

Some wireless communications devices have Global Positioning System(GPS) chipsets (or external Bluetooth™ accessories) that convertradio-frequency signals received from orbiting GPS satellites intoreal-time coordinates of longitude and latitude that are typicallyaccurate to within a few meters of the actual current location of thedevice. The current location (i.e. the coordinates of longitude andlatitude) can then be transmitted wirelessly to a recipient who hasanother wireless communications device (or via cellular base station andInternet to any other networked computing device) to thereby enable therecipient to map the coordinates using any one of a number of availablemapping applications such as BlackBerry Maps™, Google Maps or TeleNav™.Transmitting the GPS-determined current location from one mobile deviceto another enables two mobile users to rendezvous or alternativelyenables one mobile user to follow another mobile user. This sort of“consensual” tracking is described, for example, in PCT Publication WO2006/108071 (X ONE, Inc.) entitled “Location Sharing and Tracking UsingMobile Phones or Other Wireless Devices”. In a similar vein are covertGPS tracking devices that are meant to be attached to a target's vehiclewithout the knowledge and consent of the target. These covert devicesprovide only static location updates, either automatically (i.e.periodically) or upon remote request. See, for example, U.S. PatentApplication Publication 2007/0139223 (Bedenko) entitled “VehicleTracking System” and U.S. Patent Application Publication 2007/0099626(Lawrence et al.) entitled “Tracking System and Method”.

Consider the (“consensual”) scenario whereby a first mobile user wants asecond mobile user to follow him. The first mobile user can periodicallysend his GPS coordinates to the second mobile user to thus enable thesecond mobile user to plot the static position data using a mappingapplication. However, due to the time lag in generating, transmittingand mapping the position data, by the time the second mobile user seesthe “current” location of the first mobile user, the location is nolonger “current”. This is particularly problematic when the secondmobile user is following the first mobile user at high speed, such as intheir respective cars or other vehicles, in which case the time lagbetween updates may make it difficult to follow the first mobile user.This problem is further exacerbated in densely populated urban areaswhere the density of roads makes it less apparent which route or routesneed to be taken in order to reach the most recently received locationupdate of the first mobile user. Although one solution might appear toentail more frequent position updates, this would undesirably burden theonboard processors of both the sender's and recipient's devices, not tomention using up valuable wireless bandwidth with the extra over-the-airtransmissions. An improvement to this prior-art technology would thus behighly desirable in order to facilitate the tracking of one mobile userby another.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present technology will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 is a flowchart outlining steps of a method of generating andtransmitting speed, time and path data to enable a first wirelesscommunications device to track a second wireless communications device;

FIG. 2 is a block diagram of key components of a GPS-enabled wirelesscommunications device on which the present technology can beimplemented;

FIG. 3 is a high-level system diagram depicting operation of the presenttracking technology;

FIG. 4 depicts a common scenario, which is presented merely by way ofexample, in which a first mobile user would utilize the present trackingtechnology to enable a second mobile user, who has been left behind at atraffic light, to follow the first mobile user;

FIG. 5 depicts the problem, arising out of the example scenario of FIG.4, in which the second mobile user is left trying to guess which is theproper route to take to follow the first mobile user when only currentlocation updates are provided periodically to the second mobile user;

FIG. 6 depicts how a method of generating and transmitting speed, timeand path data enables the second mobile user to determine the properroute to the first mobile user;

FIG. 7 depicts an example of a map application displayed on a wirelesscommunications device of a mobile user who is tracking another mobileuser;

FIG. 8 depicts an example of an options page within a “Tracking Manager”module or application in which the user of the tracking device canconfigure various settings and preferences associated with the trackingfunction; and

FIG. 9 depicts an example of an options page within a “Follow-MeManager” module or application in which the user of the device to befollowed can configure various settings and preferences associated withthe tracking function.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

The present technology generally provides a method, wirelesscommunications device and computer program product that enable trackingof a wireless communications device. In its primary application, thistechnology enables a user of a first wireless communications device totrack or follow a second wireless communications device by receiving notonly current position data representing the current position of thesecond device, but also one or more of speed data, time data or pathdata indicative, respectively, of the speed of the device, the timecorresponding to the current position, and the path (or route) that thedevice has taken from its previously transmitted position to its currentposition.

Accordingly, an aspect of the present technology is a method of trackinga wireless communications device using another computing device. Themethod includes steps of obtaining current position data for the firstwireless communications device, obtaining one or more of speed data,time data, and path data for the first wireless communications device,and transmitting the current position data and at least one of the speeddata, time and path data from the wireless communications device to theother computing device to enable tracking of the wireless communicationsdevice using the computing device. In a main implementation, thecomputing device is a second wireless communications device so that afirst wireless communications device is used to track a second wirelesscommunications device.

Another aspect of the present technology is a computer program productthat includes code adapted to perform the steps of the foregoing methodwhen the computer program product is loaded into memory and executed ona processor of a wireless communications device. Alternatively, the codecould be loaded onto a server that is adapted to receive the raw devicedata from the first mobile device, process the data to create usefulroute-tracking information, e.g. waypoints, and then transmit theinformation (processed data) to the second mobile device.

Yet another aspect of the present technology is a wirelesscommunications device for generating and transmitting data to enabletracking of the device. The device has a GPS chipset for receiving GPSsignals and for generating current position data representing a currentposition of the device, a memory operatively connected to a processorfor storing and executing an application configured to obtain one ormore of speed data, time data and path data for the device, and aradiofrequency transmitter for transmitting the current position data inaddition to at least one of the speed data, the time data and the pathdata.

Yet a further aspect of the present technology is a computing device fortracking a mobile device. The computing device has a communications portfor receiving current position data representing a current position ofthe mobile device in addition to at least one of speed data, time dataand path data associated with the mobile device, a memory operativelyconnected to a processor for storing and executing a mapping applicationfor generating a map on which the current position is mapped, and adisplay for displaying the map in addition to the one or more of thespeed data, the time data, and the path data.

The details and particulars of these aspects of the technology will nowbe described below, by way of example, with reference to the attacheddrawings.

FIG. 1 is a flowchart outlining steps of a method of generating andtransmitting speed, time and path data to enable a first wirelesscommunications device to track a second wireless communications device.In an initial step 10, tracking of one device by another is initiated.This will be known herein as enabling or activating “follow-me” mode.Activating “follow-me” mode may be done by either the first device or bythe second device, and it may be done either manually or automatically.Automatic triggering of tracking mode can be done using a proximitydetection subsystem that detects when one device has strayed away fromanother device with which it has been paired. Bluetooth™ proximitydetection can be used to accomplish this. When one Bluetooth™ devicestrays away from its paired device, then connectivity is lost, which canthus be used to automatically trigger the activation oftracking/follow-me mode.

As depicted in the flowchart in FIG. 1, once tracking/follow-me mode hasbeen activated, the first wireless communications device (the “lead”device, i.e. the mobile device that is to be followed) obtains, at step12, current position data representing the current position (location)of the device. Current position data can be obtained using an onboardGPS chipset receiver or an external Bluetooth™-enabled GPS puck. GPSsignals from multiple orbiting GPS satellites provide a position fixaccurate to within a few meters. Assisted GPS technologies and Aided GPStechnologies can also be used to increase the time-to-first-fix (TIFF).Position data can also be obtained or supplemented using byradiolocation techniques involving triangulation of base station signalsand time of arrival calculations, though these techniques are lessaccurate than GPS, which provides sufficient accuracy for road-basednavigation.

As further depicted in FIG. 1, the method also entails a step 14 ofdetermining which additional data types to obtain and transmit. In otherwords, in addition to generating and transmitting current position data,one or more of speed data, time data and path data is obtained andtransmitted as well. As shown in FIG. 1, seven options (16-28) arepresented in FIG. 1: option 16: obtaining all data types (i.e. speed,time and path data); option 18: obtaining only speed and time data;option 20: obtaining only speed and path data; option 22: obtaining onlytime and path data; option 24: obtaining only speed data; option 26:obtaining only time data; and option 28: obtaining only path data. Inother words, the “tracking data” includes not only GPS position data butalso one or more of the speed data, time data and path data. Thetracking data can also include bearing (direction of travel). Once this“tracking data” has been obtained, it is transmitted at step 30 to theother device (i.e. the device that is following/tracking the leaddevice). For consistency of nomenclature, the first mobile user will beoperator of the lead device whereas the second mobile user will be theoperator of the tracking/following device. After the tracking data hasbeen transmitted, an assessment is made as to whether to continuetracking at step 32. If no further tracking is desired (i.e. if eitherthe first mobile user or the second mobile user has disabled thetracking function), then operations cease at step 34. If furthertracking is to be continued, then new (updated) position, speed, timeand path data is obtained and transmitted by repeating steps 12-30. Thecharacteristics and attributes of the speed, time and path data will beelaborated in greater detail below with regard to FIG. 3. As will beexplained below, this additional tracking data facilitates the task oftracking or following another mobile device. Due to the time lag betweenstatic current position data points, it is sometimes very difficult todetermine which route to take to follow the lead device. Providingspeed, time and path data in addition to current position data providesthe second mobile user (i.e. the follower or tracking party) a betteroverall picture of the movements of the first mobile user. This makes itmuch easier for the second mobile user to not only retrace the firstmobile user's exact route, but also to (possibly) predict or anticipatewhere the second mobile device is headed.

The foregoing method steps can be implemented as coded instructions in acomputer program product. In other words, the computer program productis a computer-readable medium upon which software code is recorded toperform the foregoing steps when the computer program product is loadedinto memory and executed on the microprocessor of the wirelesscommunications device.

This novel method is preferably implemented on a wireless communicationsdevice such as the BlackBerry® by Research in Motion Limited (or onother wireless handhelds, cellular phones, wireless-enabled laptops orwireless-enabled PDAs).

FIG. 2 is a block diagram depicting certain key components of a wirelesscommunications device 100. It should be expressly understood that thisfigures is intentionally simplified to show only certain components; thedevice 100 of course includes other components beyond what are shown inFIG. 2. The device 100 includes a microprocessor 102 (or simply a“processor”) which interacts with memory in the form of RAM 104 andflash memory 106, as is well known in the art. The device 100 includesan RF transceiver 108 for communicating wirelessly with one or more basestations 200. The device 100 includes a GPS receiver chipset 110 forreceiving GPS radio signals transmitted from one or more orbiting GPSsatellites 300. In terms of input/output devices or user interfaces, thedevice 100 typically includes a display 112 (e.g. a small LCD screen), athumbwheel and/or trackball 114, a keyboard 116, a USB 118 or serialport for connecting to peripheral equipment, a speaker 120 and amicrophone 122. The processor and memory thus enable a map application(among other software applications) to run on the wireless device. Themap application can interact with the GPS receiver 110 by mapping GPSposition coordinates so as to graphically display the current locationof a device.

FIG. 3 is a high-level system diagram depicting operation of the presenttracking technology. In this diagram, two GPS-enabled wirelesscommunications devices 100 are in communication with each via basestation 200 or via separate base stations if the devices are furtherapart. In any event, the devices are connected to each other via awireless network enabling transmission and reception of data packets. Inaddition, as shown in FIG. 3, the wireless communications devices 100are in receipt of GPS signals from a plurality of GPS satellites 300.The lead device “Mobile 1” (which is associated with the first mobileuser) obtains and transmits current position data, speed data, time dataand path data (or a subset thereof) to the device of the second mobileuser (“Mobile 2”) via base station 200 (and its wireless network).Mobile 2 receives this current position data, speed data, time data andpath data (or a subset thereof) and then presents this “tracking data”to the second mobile user graphically and/or audibly.

For example, the second wireless communications device can map thecurrent position and path with superimposed speed and time informationof the first mobile user on a map, as will be shown by way of examplebelow in FIG. 7. Alternatively or additionally, the tracking data can bepresented audibly such as in the form of audible reports (e.g. “Theparty you are following was 2 minutes ago at the corner of 1^(st) Avenueand Bank Street, traveling eastbound on 1^(st) Avenue at 50 km/h”)and/or as turn-by-turn instructions to navigate the same path as takenby the first mobile user. In addition to receiving the tracking data,the second mobile device receives its own GPS signals and converts theseinto its own GPS fix. Its own current position can be plotted on the mapto show relative positions. Alternatively or additionally, its owncurrent position fix can be used by navigation software to reroute thesecond mobile user over a different path to catch up to the first mobileuser. In other words, navigation software can be used to determine amore optimal route to reach the most recently received current positionof the first mobile user and to present this option to the second mobileuser, who may either choose to follow the exact path taken by the firstmobile user or to take the suggested, “more optimal” route to catch upto the first mobile user.

For the purposes of this specification, “speed data” means datapertaining to the speed, velocity or rate of travel of the device beingfollowed. The speed data can be an average speed determined using therate of change of (GPS-determined) position over time. Alternatively,speed data can be an instantaneous velocity obtained using a velocitysensor/transducer that is embedded or connected to the device. As afurther alternative, the device may receive speed data wirelessly (e.g.via Bluetooth™ from a vehicle speed sensor). The speed data may includethe speed as a scalar value (just the magnitude) or it may include avelocity vector (both speed and direction). Where path data is alsoprovided, the velocity vector is unnecessary since direction is alreadyknown from the path data). Speed data is useful to the recipient (secondmobile user) to know how fast the first mobile user is traveling, andthus whether he should consider traveling faster to catch up.

For the purposes of this specification, “time data” means datapertaining to the actual time of day of the first mobile device when itis at a particular location or the time elapsed since the last positionfix or the time elapsed between the position fix and the receipt of thetracking data by the second mobile user. In other words, time dataaccompanying the GPS position fix gives important context to thelocation data by telling the recipient (the second mobile user) that thefirst mobile user was at that particular location at that particulartime. Merely providing the location is not nearly as informative sincethe recipient might not have a good sense as to exactly when the firstmobile user was at that location. In other words, time data enables therecipient to know how old or stale the position fix really is.

For the purposes of this specification, “path data” means datapertaining to the path or route that the first mobile device has taken.This can be provided as path segments (just the portion of the path thatthe device has travelled since the previously fix was obtained) or as acumulative path that shows the entire path the device has travelledsince tracking was initiated. Alternatively, the receiving device canstore all the path data but only display the cumulative path data thatfits within the bounding box of at the map scale selected. The path datamay include a sequential list of all street names and highway numbersthat define the path taken by the lead device along with the directiontaken along each one, thus constituting navigation instructions for therecipient. Alternatively, the path data can be vector data that enablesthe recipient device to render a map of the path with the pathhighlighted using one of any number of standard mapping applications.Alternatively, a bitmap showing the route/path highlighted can begenerated by the lead device and transmitted to the recipient device forimmediate viewing onscreen. Optionally, the efficiency of this trackingmethod or following method can be improved by simplifying the path datato reduce the amount of data being generated and transmitted withoutunduly sacrificing travel path fidelity. Techniques such as the DouglasPeuker line simplification algorithm can be used to reduce the number ofpoints required to describe a path (e.g. by eliminating common pointsalong a straight line).

As will appreciated, the path data effectively subsumes the currentposition data because the destination point of each path segment of thepath data corresponds to each of the position fixes. The path data ispresented as a graphically highlighted route on a map (with optionalnavigation instructions presented either graphically or audibly). Thecurrent position fix is thus used to define the endpoint or destinationof the path. The second mobile device (the following device) mayoptionally present the destination of the path (which is defined by theGPS position fix) either as a destination street address (e.g. 123 MainStreet) and/or as longitude and latitude coordinates.

In another implementation, the second mobile device could alsooptionally present a distance to the first mobile device. This distancecould be in terms of actual road distance in kilometres (or miles) ormeters (or yards). The distance could alternatively be presented interms of straight-line distance (the distance “as a crow flies”) alongwith the compass bearing (e.g. “northeast” or 045 degrees). In additionto, or in lieu of, distance, an estimated time (“estimated time ofarrival”) to the current location of the first mobile user can beprovided or the time to convergence can be presented (the time requiredto catch up to the first mobile user or to arrive within a prescribedrange of the first user, such as, for example, the range at which theBluetooth™ proximity detection was triggered). Thus, in this variant ofthe implementation, a “trip computer” module can be provided as asoftware application on the device to compute various distances, compassbearings and times.

FIG. 4 depicts a common scenario, which is presented merely by way ofexample, in which a first mobile user (“Mobile 1”) would utilize thepresent tracking technology to enable a second mobile user (“Mobile 2”),who has been left behind at a traffic light, to follow the first mobileuser. The present technology is particularly useful for mobile userstravelling in road vehicles where the speeds involved, the volume oftraffic on the roads, the interference of traffic lights, and the numberof routing options make it is easy to lose track of the vehicle beingfollowed. Although cars are depicted by way of example, the scenariodescribed with regard to this and the following figures is equallyapplicable to other road vehicles (e.g. trucks, vans, buses,motorcycles, scooters), or to off-road vehicles (e.g. snowmobiles,ATVs), or to watercraft (e.g. motorboats, yachts, sailboats, personalwatercraft, jet skis) or to bicyclists or even to mobile users who aremerely walking on foot.

FIG. 5 depicts the problem, arising out of the example scenario of FIG.4, in which the second mobile user (“Mobile 2”) is left trying to guesswhich is the proper route to take to follow the first mobile user(“Mobile 1”) when only current location updates are providedperiodically to the second mobile user. In this example scenario, thecar associated with Mobile 1 is no longer within visual range of the carassociated with Mobile 2 (having been left behind earlier on at atraffic light). Therefore, the occupants of the car associated withMobile 2 would not necessarily know which way to go (presuming, for thesake of illustration, that the occupants of the car associated withMobile 2 do not know the proper route to take to reach the park by thelake).

FIG. 6 depicts how a method of generating and transmitting speed, timeand path data enables the second mobile user (“Mobile 2”) to determinethe proper route to the first mobile user “Mobile 1”). In this example,which is again merely provided to illustrate the use of the presenttechnology, three data transmissions are provided by Mobile 1 to Mobile2 at discrete points to enable Mobile 2 to follow Mobile 1. At time T1,when Mobile 1 turns off Highway 206 South (206S) onto Bridge Street,Mobile 1 transmits its current position as well as its speed, time andpath to Mobile 2. The path data, for example, might be a pre-generatedbitmap (or vector path data enabling rendering of a map) showing asegment of Highway 17 followed by an exit onto Highway 206S.Turn-by-turn navigation instructions in graphical or audible form couldalso be provided. At time T2, when Mobile 1 turns onto the bridge,another transmission of tracking data is sent, again providing an updateof the current position of Mobile 1 along with its updated speed, timeand path. Again, at time T3, Mobile 1 transmits updated position, speed,time and path data to Mobile 2. The three data transmissions provideMobile 2 with enough information to enable Mobile 2 to correctly exitonto Highway 206S, to correctly turn onto Bridge Street and to correctlyfollow the bridge over the lake to the park which is the destinationthat Mobile 1 intended.

FIG. 7 depicts an example of a map application displayed on a wirelesscommunications device of a mobile user who is tracking another mobileuser. An application interface 350 is provided merely by way of exampleto illustrate one manner of presenting the tracking data. As will bereadily appreciated, other interfaces presenting the data in othermanners, i.e. having a different “look and feel” would be of course bepossible. Likewise, the interface could present more data or less datathan what is shown in this example. In addition to the graphicalrepresentation of the tracking data, audible reports can be used tosupplement or replace certain aspects of the tracking data, e.g. usingtext-to-speech turn-by-turn navigation that read aloud the street names,audibly reporting speed, time and position data in addition todisplaying it onscreen.

As depicted on the example interface 350 shown in FIG. 7, the currentlocation of the tracking party (the second mobile user) is shown by acar icon 360 (although other icons can be selected by the user to fitthe circumstance). Car icon 370 represents the GPS position fix at timeT1 of the first mobile user that the second mobile user is tracking assoon as tracking/follow-me mode is initiated. The first set of trackingdata packets is transmitted to the second mobile user to report that,for example, at time T1=12:05 pm, the first mobile user was traveling ata speed of 50 km/h eastbound on 1^(st) Avenue. A short while later, asecond transmission is sent to update the current position, speed, timeand path. Car icon 380 represents the updated position at time T2 which,in this example, is five minutes later at 12:10 pm (although it shouldbe appreciated that updates can be provided more frequently, e.g. onceper minute) or less frequently, as configured by the users. Lessfrequent updates can be provided in rural environments where the routingoptions are fewer and where the users desire to conserve deviceresources for other uses or applications. More frequent updates would ofcourse be useful in densely populated urban areas where the number ofroute choices are high and thus the likely of getting lost is higher.The frequency of updates can also be managed or modulated based on thestate of the leading user (first mobile user) and the distance betweenthe first mobile user and the second mobile user (the following party).For example, updates may be sent less frequently if the lead user (firstmobile user) is (a) stopped; (b) travelling at high speed in a constantdirection; or (c) a large distance from the following vehicle (whichrequire feedback from the tracking party/second mobile user). Sendingupdates less frequently reduces the burden on the mobile devices and onthe wireless link. It should also be noted that path data can be moreeasily compressed if it is sent in larger segments. The rate of travel(i.e. speed) of the lead user (first mobile user) can also be animportant factor in determining whether there is a latency effect in theprocess of generating, transmitting, receiving and displaying the pathdata. In other words, if there is a significant or noticeable delay(“latency”) in providing the path data to the tracking party, then themethod should take this latency or delay into account by anticipating orpredicting where the first mobile user (lead user) is likely to be, orwhere the lead user is heading, at the time the path data is actuallydisplayed onscreen on the device of the second mobile user.

Referring still to the example of FIG. 7, the second data transmissionreports that, for example, at time T2=12:10 pm, the second mobile userwas traveling 40 km/h eastbound on 3^(rd) Avenue. The path data wouldprovide a route as shown between car icons 370 and 380, i.e. the routetraversed between times T1 and T2. Written instructions and/or audibleinstructions would provide turn-by-turn navigation, e.g. “Go East on 1stAve, Turn North (left) on Bank Street, Turn East (right) on 3rd Avenue,go past Hwy 1.”

Still referring to the example presented in FIG. 7, a third update isprovided to the second mobile user by transmitting updated tracking dataat time T3, whose position is represented by car icon 390. At timeT3=12:15 pm, which is again five minutes later, the first mobile user istraveling 30 km/h eastbound on 4^(th) Avenue. The path data would updatethe route as shown between car icons 380 and 390 and would optionallyalso provide navigation instructions in written or audible format, e.g.“Turn South (right) on Oak Street, Turn East (left) on 2nd Ave, TurnNorth (left) on Maple Street. Turn east (right) on 4th Ave.” The path,speed and time data facilitate the second mobile user's task offollowing the first mobile user through the city streets. As mentionedearlier, the application may optionally compute an alternate route (e.g.east on 1^(st) Avenue and left on Alder) rather than slavishly followthe exact path taken by the first mobile user. In any event, the secondmobile user may be presented with a choice between the exact route andthe alternate route or the user may configure the device toautomatically provide either the exact route or the alternate route(where the alternate route is shorter).

FIG. 8 depicts an example of an options page 400 within a “TrackingManager” module or application in which the user of the tracking device(the second mobile user) can configure various settings and preferencesassociated with the tracking function. For example, the options page 400enables the user to activate or deactivate the tracking function, todetermine which types of data are to be displayed and in what particularformat. The user can also specify the frequency with which updatesrequests are sent to the device belonging to the first mobile user beingfollowed. The user can also specify whether he prefers to receivepre-generated bitmaps (i.e. bitmaps generated by the first mobile useron his device) or to receive the raw data which is then to be mapped bythe receiving device. An optional path log can be provided to enable theuser to review or revisit all of the navigation instructions acquiredwhile following the first mobile user along the various path segments.An optional “Map It Now” function will bring up a map with the pathshighlighted or otherwise emphasized.

In one implementation, a breadcrumb path (composed of waypoints or pathsegments) can also be stored (along with optional reverse navigationinstructions) to enable the user to retrace his path to return to thestarting point where the following began. This breadcrumb functionand/or set of reverse path instructions is particularly useful insituations when the second mobile user has followed the first mobileuser through unfamiliar places and then wishes to return alone(unguided) to the point of where the following originated. For example,consider the scenario where the second mobile user has followed thefirst mobile user to a cottage through unfamiliar terrain and thenwishes to return home alone after dark. The user activates thebreadcrumb function to obtain the route home without having to worryabout trying to navigate unfamiliar roads in the dark. The breadcrumbfunction can also include stored travel times to inform the user of howmuch time it took to travel between the waypoints when following thefirst mobile user. The breadcrumb function can also optionally providedistances (audibly or graphically) and travel speeds for each pathsegment between waypoints. This is useful for the user to know whatspeed is reasonable to travel (when perhaps speed limits are not easilyvisible) and how many kilometres or miles he has to travel to the nextwaypoint. The breadcrumb function can also optionally re-compute thetravel time to the next waypoint based on the actual travel speed on thereturn leg of the voyage (which may happen to differ from the travelspeed for the first leg of the voyage). In addition to turn-by-turnretracing of steps, another breadcrumb function that can be implementedis an off-road breadcrumb function which is usable in scenarios wherethe lead user (first mobile user) is not traveling on roads known to thenavigation software, in which case breadcrumbs or waypoints are definedat specific positions to enable the tracking party to follow the samepath or paths taken by the lead user. For example, this would be usefulfor off-road vehicles, all-terrain vehicles, watercraft, boats,aircraft, helicopters, or pedestrians or hikers who wish to follow thelead user but without reference to specific defined roadways.

In a variant on this implementation, the device can be configured torecord audible input from the user (via the microphone on the device)that thereby enables the user to comment on personally definedwaypoints. This recorded waypoint commentary can be stored inassociation with an actual GPS position fix (or an interpolated positionbetween adjacent fixes based on travel time and travel speed). When theuser retraces his route, the waypoint commentary is played audibly viathe device speaker to remind the user of landmarks or waypoints that arepersonally meaningful. For example, when passing a particular gasstation, the user may record “We are turning at a bright orange gasstation by a McDonald's.” Recording may be voice-activated (hands-free)or triggered by saying a predetermined specific word or phrase like“Record Waypoint Comment” that voice-recognition software on the devicerecognizes. When the user returns, the waypoint comment is playedthrough the speaker to alert the user of the particular waypoint that heconsidered meaningful.

FIG. 9 depicts an example of an options page 500 within a “Follow-MeManager” module or application in which the user of the device to befollowed can configure various settings and preferences associated withthe tracking function. The follow-me manager enables the user of thedevice being followed (the first mobile user) to manually enable thefollow-me mode, to automatically trigger the follow-me mode based onBluetooth™ proximity detection (loss of Bluetooth™ connectivity), or todisable follow-me mode (to refuse to receive tracking data). There couldbe other options too, for example, to buffer the tracking data and toask the second mobile user whether he would like to accept the trackingdata and if the second device replies in the affirmative, then the firstdevice enters follow-me mode. Instead of using loss of Bluetooth™connectivity to trigger follow-me mode, Bluetooth™ proximity detectioncan also be used to signal availability to enter into follow-me mode.When the device is set to “discoverable” mode, the Bluetooth™-enableddevice sends a signal indicating that it is ready and available to“pair” with another Bluetooth™ device. For example, if first and secondmobile users are planning to meet up so that one can follow the other,the two users put their devices into “discoverable” mode in order toallow the two devices to pair up when they have come suitably withinrange, e.g. up to approximately 100 meters for a Class I Bluetooth™device, or alternatively, to within 10 meters for a Class II device. Inaddition, some or all of the data exchanged can be accomplished usingthe Bluetooth™ connection (for Class I devices) although due to thelimited range (100 m), it is preferable to rely on the wireless link. Inanother variant, the device could use the Bluetooth™ link and thenswitch over to the cellular channel (the “normal” wireless link) whenthe devices get close to their maximum range.

Furthermore, as shown by way of example in FIG. 9, the user canconfigure the follow-me manager to actively generate and transmit data(active mode) or to await requests for data from the device that isfollowing (passive mode). The user of the device being followed canaccept to generate bitmaps on request (which puts more burden on thedevice being followed) or to only send the raw data (which shifts thecomputational burden to the device doing the following).

As further shown in FIG. 9, the follow-me manager can enable the user tospecify whether to allow generation and transmission of current positiondata, speed data, time data and path data. For speed data, the firstmobile user can specify whether to send only the speed or the speed plusdirection (velocity vector). Finally, as shown in FIG. 9 again by way ofexample only, the permitted frequency of updates can be regulated by thefirst mobile user. Frequent updates are courteous to the party beingfollowed (i.e. providing the most tracking data) but are also mostexpensive in terms of data charge and airtime and use up the processingresources of the device. Infrequent transmissions, on the other hand,use up less resources, keeping the device's processor and RAM free forhandling other applications. This feature regulates what the firstmobile user is willing to allocate. In effect, the actual frequency oftransmissions can be a function of what the first mobile user is willingto provide and what the second mobile user is requesting or it can be afunction of the various parameters mentioned above, namely the rate oftravel, distance between the mobile users, etc.

In another implementation, the frequency of updates can be based on afeedback loop that requires feedback from the follower. For example,instead of the first mobile device (lead user) transmitting completesets of route data representing all the route information between theirrespective positions, a more efficient way of transmitting data mightentail parcelling the route data and transmitting only small batches orparcels of route information at a time to the follower (second mobileuser) with a waypoint marker. When the follower reaches the waypointmarker, the follower's device signals to the lead user that more data isneeded. The waypoint marker can be set a certain distance (or timeequivalent) ahead of the end of the current segment of route data sothat the follower does not run out of route data before more can besupplied. In other words, when the follower reaches the waypoint marker,the follower device signals the lead device that the next segment ofroute information is needed. As a corollary benefit, the lead userreceives confirmation that the follower has reached the waypoint markerand is thus “on track”. This gives the lead user a more granular senseof where the follower is currently positioned, permitting the user tooptionally make adjustments in course, speed, etc. to accommodate thefollower. Requesting more data from the lead device can be accomplishedin a manner very similar to a “more” (data) request made in respect of areceived e-mail, i.e. just a single bit (flag) indicating that thewaypoint has been reached and that, consequently, more data is requiredto describe or depict the next segment along the route.

Although the foregoing has presumed one follower and one lead device,this technology can also be used to multicast tracking data to more thanone follower. This is the case where a first mobile user wishes to leada group of friends all in different cars to his cottage.

It should also be appreciated that the follower could also be a static(non-mobile) follower, i.e. a user of a stationary computing device, whois only visually following, or visually tracking, the lead user'smovements. Although the computing device is preferably a wirelesscommunications device, the computing device can also be a desktopcomputer, laptop, or other such computing device that has a processor,memory and communications port for receiving the real-time trackingdata. Even for a fixed computing device, the communications port can bewireless or wire-line.

This new technology has been described in terms of specificimplementations and configurations which are intended to be exemplaryonly. The scope of the exclusive right sought by the Applicant istherefore intended to be limited solely by the appended claims.

1. A method of tracking a first wireless communications device using asecond wireless communications device, the method comprising: receivinguser input to enable tracking of the first wireless communicationsdevice; and in response to receiving the user input, enabling thetracking of the first wireless communications device by the secondwireless communications device by: obtaining current position data forthe first wireless communications device; and transmitting the currentposition data from the first wireless communications device to thesecond wireless communications device to enable tracking of the firstwireless communications device using the second wireless communicationsdevice.
 2. The method as claimed in claim 1 further comprisingtransmitting one or more of speed data, time data and path data.
 3. Themethod as claimed in claim 2 further comprising receiving preferencedata from the second wireless communications device indicating which ofthe speed data, time data and path data is to be transmitted by thefirst wireless communications device to the second wirelesscommunications device.
 4. The method as claimed in claim 2 furthercomprising receiving further user input to specify which of the speeddata, time data and path data is to be transmitted by the first wirelesscommunications device to the second wireless communications device. 5.The method as claimed in claim 1 further comprising defining waypointsfor segments of a path and sending the path data in segments to thesecond wireless communications device.
 6. The method as claimed in claim5 further comprising receiving an indication from the second wirelesscommunications device that the second wireless communications device hasreached a waypoint and sending the path data for a successive segment tothe second wireless communications device.
 7. A non-transitorycomputer-readable medium comprising code which, when loaded into memoryand executed on a processor of a first wireless communications device,enables a tracking mode for sharing tracking data with a second wirelesscommunications device by: receiving user input to enable tracking of thefirst wireless communications device by the second wirelesscommunications device; and in response to receiving the user input,enabling the tracking of the first wireless communications device by thesecond wireless communications device by: obtaining current positiondata for the first wireless communications device; and transmitting thecurrent position data from the first wireless communications device tothe second wireless communications device to enable tracking of thefirst wireless communications device using the second wirelesscommunications device.
 8. The computer-readable medium as claimed inclaim 7 further comprising transmitting one or more of speed data, timedata and path data.
 9. The computer-readable medium as claimed in claim8 further comprising code for receiving preference data from the secondwireless communications device indicating which of the speed data, timedata and path data is to be transmitted by the first wirelesscommunications device to the second wireless communications device. 10.The computer-readable medium as claimed in claim 8 further comprisingcode for receiving further user input to specify which of the speeddata, time data and path data is to be transmitted by the first wirelesscommunications device to the second wireless communications device. 11.The computer-readable medium as claimed in claim 7 further comprisingdefining waypoints for segments of a path and sending the path data insegments to the second wireless communications device.
 12. Thecomputer-readable medium as claimed in claim 11 further comprising codefor receiving an indication from the second wireless communicationsdevice that the second wireless communications device has reached awaypoint and sending the path data for a successive segment to thesecond wireless communications device.
 13. A first wirelesscommunications device for generating and transmitting data to enabletracking of the first wireless communications device by a secondwireless communications device, the first wireless communications devicecomprising: a user interface for receiving user input to enabletracking; a Global Satellite Navigation System (GNSS) receiver forreceiving GNSS signals and for generating current position datarepresenting a current position of the first wireless communicationsdevice; a processor operatively connected a memory, the processor beingconfigured to cause a radiofrequency transmitter to transmit the currentposition data of the first wireless communications device to the secondwireless communications device.
 14. The first wireless communicationsdevice as claimed in claim 13 wherein the processor causes theradiofrequency transmitter to transmit one or more of speed data, timedata and path data.
 15. The first wireless communications device asclaimed in claim 14 further comprising receiving preference data fromthe second wireless communications device indicating which of the speeddata, time data and path data is to be transmitted by the first wirelesscommunications device to the second wireless communications device. 16.The first wireless communications device as claimed in claim 14 furthercomprising code for receiving further user input to specify which of thespeed data, time data and path data is to be transmitted by the firstwireless communications device to the second wireless communicationsdevice.
 17. The first wireless communications device as claimed in claim14 further comprising code for defining waypoints for segments of a pathand sending the path data in segments to the second wirelesscommunications device.
 18. The first wireless communications device asclaimed in claim 17 wherein the radiofrequency transmitter receives anindication from the second wireless communications device that thesecond wireless communications device has reached a waypoint and sendsthe path data for a successive segment to the second wirelesscommunications device.